This invention relates to an ink jet head which jets ink from a nozzle hole by applying an electric voltage to an electrode to deform the shape of the space making up an ink chamber, to a method of manufacturing the ink jet head, to an ink jet printer and to a method of manufacturing the ink jet printer.
There is a letter printing apparatus of the ink jet method which jets ink from a nozzle hole by applying an electric voltage to an electrode to deform the partition wall forming an ink chamber.
If one wishes to carry out image recording of high quality at a high speed using an ink jet head of a conventional type, an ink jet head having a large number of nozzle holes arrayed in a line is required. For such kind of an ink jet head having a large number of nozzles arrayed in a line, from the view point of practical use, it is desired one that has a high driving efficiency, a light weight, a low price, a good workability, and a high strength.
Further, because a polarized piezoelectric ceramic plate has a limit in length for reasons of manufacturing, it has been practiced that a plurality of ink chambers are formed by partition walls in a polarized piezoelectric ceramic plate, and a plurality of such polarized piezoelectric ceramic plates having a plurality of ink chambers are put side by side and bonded by an adhesive; however, in connecting a plurality of polarized piezoelectric plates, it is difficult to adjust the positions of them to keep the intervals between adjacent ink chambers at the connecting portions equal to one another, which makes it difficult to obtain a high-precision ink jet head.
Furthermore, among ink jet heads of the share-mode type which jets ink by deforming the ink chamber, it has been known a chevron type ink jet head which is desirable for carrying out a high-speed and high-quality image recording; however, according to the conventional method of manufacturing the chevron type head, polarized piezoelectric ceramic plates having a plurality of grooves are disposed side by side, and another polarized piezoelectric ceramic plates having a plurality of grooves are superposed and arrayed on them to build an ink jet head having a plurality of ink chambers divided by partition walls; this requires a difficult work of making two piezoelectric plates having mutually coincident positions (of grooves), which makes it difficult to obtain a high-precision ink jet head.
This invention has been done in view of the above-described points, and it is an object of it to provide an ink jet head and an ink jet printer which is capable of carrying out a high-speed and high-quality image recording and is of low cost and of high precision and a method of manufacturing them.
In order to solve the above-mentioned problems and to accomplish the object, the structure of this invention has been made as follows:
(1) In an ink jet head or an ink jet printer which jets ink from nozzle holes by applying an electric voltage to an electrode to deform the shape of a space forming an ink chamber, the ink chamber is formed by being surrounded by two piezoelectric base plates which are given polarization and face each other and two non-piezoelectric base plates facing each other, and the piezoelectric base plates have a structure such that each of them is made up of at least two lamination layers of a piezoelectric material and the lamination layer surface is approximately parallel to the non-piezoelectric base plates and the polarizing directions of these two lamination layers of the piezoelectric material are opposite to each other, and an electrode is provided on the surface of each of the piezoelectric base plates and the non-piezoelectric base plates facing the ink chamber.
According to the structure (1), since the ink jet head is constructed such that the ink chamber is formed by being surrounded by two piezoelectric base plates which are given polarization and face each other and two non-piezoelectric base plates facing each other, and the piezoelectric base plates have a structure such that each of them is made up of at least two lamination layers of a piezoelectric material and the lamination layer surface is approximately parallel to the non-piezoelectric base plates and the polarizing directions of these two lamination layers of the piezoelectric material are opposite to each other, and an electrode is provided on the surface of each of the piezoelectric base plates and the non-piezoelectric base plates facing the ink chamber; in comparison with the case that an electrode is provided only to the piezoelectric base plates without being provided to the non-piezoelectric base plates, the work to provide the electrode is easy so that the ink jet head is of low cost and capable of driving the piezoelectric base plates at a low voltage, has a high-efficiency driving performance owing to a large amount of deformation in the piezoelectric base plates, is capable of coping with multiple nozzles, has the capability of high-frequency driving, and jets small droplets with multi-gradation so that an image recording can be conducted at a high-speed with high-quality image.
(2) The ink jet head or the ink jet printer described in (1), wherein an electrode is provided on the ink chamber facing surface of each of the piezoelectric base plates which are given polarization and face each other and on the ink chamber facing surface of either one of the non-piezoelectric base plates facing each other.
According to this structure (2), since an electrode is provided on the ink chamber facing surface of each of the piezoelectric base plates which are given polarization and face each other and on the ink chamber facing surface of either one of the non-piezoelectric base plates facing each other, in comparison with the case that an electrode is provided only to the piezoelectric base plates without being provided to the non-piezoelectric base plates, the work to provide the electrode is easy so that the ink jet head is of low cost and capable of driving the piezoelectric base plates at a low voltage, has a high-efficiency driving performance owing to a large amount of deformation in the piezoelectric base plates, is capable of coping with multiple nozzles, has the capability of high-frequency driving, and jets small droplets with multi-gradation so that an image recording can be conducted at a high-speed with high-quality image.
(3) The ink jet head or the ink jet printer described in (1) or (2), wherein the ink chamber is formed in multi-stages.
According to this structure (3), since the ink chamber is formed in multi-stages, it can carry out a more high-speed and high-quality image recording and can improve resolution of the image with multiple nozzles of the multi-stage ink chamber.
(4) The ink jet head or the ink jet printer described in (1) or (3), wherein the piezoelectric base plates are shaped in a flat surface or a curved surface.
(5) The ink jet head or the ink jet printer described in (1) or (4), wherein the piezoelectric base plates have at least two lamination layers which have different lengths in the layer laminating direction.
According to this structure (5), because the piezoelectric base plates have at least two layers which have different lengths in the layer laminating direction, the shape of the space making up the ink chamber can be deformed in a manner corresponding to the position of a nozzle hole, and ink can be jetted from the nozzle hole more efficiently.
(6) The ink jet head or the ink jet printer described in (1) or (5), wherein the piezoelectric base plates have at least one layer made of a non-piezoelectric material.
According to this structure (6), because the piezoelectric base plates have at least one layer made of a non-piezoelectric material, ink can be jetted from a nozzle hole efficiently by deforming the shape of the space making up the ink chamber variously.
(7) In an ink jet head or the ink jet printer which jets ink from nozzle holes by applying an electric voltage to an electrode to deform an ink chamber which is partitioned by partition walls, a plurality of piezoelectric base plates which are given polarization are disposed side by side on a non-piezoelectric base plate, a plurality of grooves are provided in each of the piezoelectric base plates, and another non-piezoelectric base plate is provided on these piezoelectric base plate so that a plurality of ink chambers partitioned by partition walls are provided.
According to this structure (7), since a plurality of piezoelectric base plates which are given polarization are disposed side by side on a non-piezoelectric base plate, a plurality of grooves are provided in each of the piezoelectric base plates, and another non-piezoelectric base plate is provided on these piezoelectric base plate so that a plurality of ink chambers partitioned by partition walls are provided, an ink chamber can be formed without lowering positional precision and it is possible to obtain a long-sized line head which is of low cost, has a high precision, and is long in its lengthwise direction; thus, a high-speed and high-quality image recording can be carried out.
(8) The ink jet head or the ink jet printer described in (7), wherein the grooves are formed at the connecting portions of the plurality of piezoelectric base plates.
According to this structure (8), because grooves are formed at the connecting portions of the plurality of piezoelectric base plates, the positional precision of the ink chamber can be improved further more.
(9) In an ink jet head or the ink jet printer which jets ink from nozzle holes by applying an electric voltage to an electrode to deform an ink chamber which is partitioned by partition walls, a piezoelectric base plate comprising at least two layers of piezoelectric material whose polarizing directions are opposite to each other are disposed on a non-piezoelectric base plate, a plurality of grooves are provided with a predetermined interval in each of the piezoelectric base plates, and another non-piezoelectric base plate is provided on these piezoelectric base plate so that a plurality of ink chambers partitioned by partition walls are provided.
According to this structure (9), since a piezoelectric base plate comprising at least two layers of piezoelectric material whose polarizing directions are opposite to each other are disposed on a non-piezoelectric base plate, a plurality of grooves are provided with a predetermined interval in each of the piezoelectric base plates, and another non-piezoelectric base plate is provided on these piezoelectric base plate so that a plurality of ink chambers partitioned by partition walls are provided, the ink chambers are formed in the piezoelectric base plates without the deviation of grooves, it is possible to obtain a low-cost and high-precision line head, and a high-speed and high-quality image recording can be carried out.
(10) The ink jet head or the ink jet printer described in (9), wherein grooves are formed at the connecting portions of the plurality of piezoelectric base plates.
According to this structure (10), because grooves are formed at the connecting portions of the plurality of piezoelectric base plates, ink chambers are formed without lowering of the positional precision more reliably.
(11) The ink jet head or the ink jet printer described in one of (1) through (10), wherein the piezoelectric base plates is made of a non-metallic material.
According to this structure (11), since the piezoelectric base plates is made of a non-metallic material, the partition walls of the ink chamber can be deformed more reliably.
(12) The ink jet head or the ink jet printer described in one of (1) through (10), wherein the material of the non-metallic material is at least one selected from alumina, aluminum nitride, zirconia, silicon, silicon nitride, silicon carbide, and quartz.
According to this structure (12), since the material of the non-metallic material is at least one selected from alumina, aluminum nitride, zirconia, silicon, silicon nitride, silicon carbide, and quartz, the piezoelectric base plates can be reliably supported even if the partition walls of an ink chamber are deformed.
(13) The ink jet head or the ink jet printer described in one of (7) through (12), wherein a surface roughness of the bonded surfaces between the non-piezoelectric base plate and the piezoelectric base plates is not larger than 1.0 xcexcm.
According to this structure (14), since a surface roughness of the bonded surfaces between the non-piezoelectric base plate and the piezoelectric base plates is not larger than 1.0 xcexcm, it is possible to prevent a soft high molecular adhesive (for example, epoxy resin) from entering into the concave portions on the bonded surfaces, the film thickness of the adhesive is practically limited to a minimum, and it is possible to avoid the lowering of sensitivity and the rise of the electric voltage owing to the lowering of the driving force of the piezoelectric base plates.
(14) The ink jet head or the ink jet printer described in one of (9) through (13), wherein a surface roughness of the bonded surfaces between piezoelectric materials of the piezoelectric base plates having at least two layers of the piezoelectric materials is not larger than 1.0 xcexcm.
According to this structure (14), since a surface roughness of the bonded surfaces between piezoelectric materials of the piezoelectric base plates having at least two layers of the piezoelectric materials is not larger than 1.0 xcexcm, it is possible to prevent a soft high molecular adhesive (for example, epoxy resin) from entering into the concave portions on the bonded surfaces, the film thickness of the adhesive is practically limited to a minimum, and it is possible to avoid the lowering of sensitivity and the rise of the electric voltage owing to the lowering of the driving force of the piezoelectric base plates.
(15) The ink jet head or the ink jet printer described in one of (7) through (14), wherein the bonded surfaces between the non-piezoelectric base plate and the piezoelectric base plates are subjected to a plasma treatment or a U.V. treatment.
According to this structure (15), since the bonded surfaces between the non-piezoelectric base plate and the piezoelectric base plates are subjected to plasma treatment or UV treatment, organic contaminants can be cleaned and removed and wetting ability of the surfaces for the adhesive is improved over the whole surface to eliminate poor bonding such as minute bubble remains, and owing to it, poor driving for the piezoelectric base plates can be eliminated.
(16) The ink jet head or the ink jet printer described in one of (8) through (14), wherein the bonded surfaces between piezoelectric material layers of the piezoelectric base plates having at least two layers of the piezoelectric material are subjected to plasma treatment or UV treatment.
According to this structure (16), since the bonded surfaces between piezoelectric material layers of the piezoelectric base plates having at least two layers of the piezoelectric material are subjected to plasma treatment or UV treatment, organic contaminants can be cleaned and removed and wetting ability of the surfaces for the adhesive is improved over the whole surface to eliminate poor bonding such as minute bubble remains, and owing to it, poor driving for the piezoelectric base plates can be eliminated.
(17) A method of manufacturing an ink jet head or an ink jet head printer which jets ink from nozzle holes by applying an electric voltage to an electrode to deform a shape of a space forming an ink chamber, comprising steps of forming the ink chamber by surrounding by two piezoelectric base plates which are given polarization and face each other and two non-piezoelectric base plates facing each other and providing an electrode on each of the piezoelectric base plates, wherein the piezoelectric base plates have a structure such that each of them is made up of at least two layers of piezoelectric material, the layer surfaces are approximately parallel to the non-piezoelectric base plates and the polarizing directions of these two adjacent layers made of piezoelectric material are opposite to each other.
According to this method (17), since the ink chamber is formed by surrounding by two piezoelectric base plates which are given polarization and face each other and two non-piezoelectric base plates facing each other, an electrode is provided on each of the piezoelectric base plates, and the piezoelectric base plates have a structure such that each of them is made up of at least two layers of piezoelectric material, the layer surfaces are approximately parallel to the non-piezoelectric base plates and the polarizing directions of these two adjacent layers made of piezoelectric material are opposite to each other, it can be manufactured an ink jet head which is of low cost, can drive the piezoelectric base plates at a low voltage, has a high-efficiency driving performance owing to a large amount of deformation in the piezoelectric base plates, is capable of coping with multiple nozzles, has the capability of high-frequency driving, can jet small droplets with multi-gradation so that an image recording can be conducted at a high-speed with high-quality image.
(18) The method of manufacturing an ink jet head or an ink jet printer described in (17), wherein the ink chamber is formed by pasting the piezoelectric base plate composed of at least two layers on the non-piezoelectric base plate, machining the pasted piezoelectric base plate so as to provide grooves, and pasting another non-piezoelectric base plate onto the piezoelectric base plate.
According to this method (18), since the ink chamber is formed by pasting the piezoelectric base plate composed of at least two layers on the non-piezoelectric base plate, machining the pasted piezoelectric base plate so as to provide grooves, and pasting another non-piezoelectric base plate onto the piezoelectric base plate, an ink chamber can be formed at a low cost and with a high precision owing to the ease of the positional adjustment of the ink chamber.
(19) The method of manufacturing an ink jet head or an ink jet described in (17), wherein the ink chamber is formed by pasting the piezoelectric base plate, which has been machined to have a groove, on the non-piezoelectric base plate, and pasting another non-piezoelectric base plate onto the piezoelectric base plate.
According to this method (19), since the ink chamber is formed by pasting the piezoelectric base plate, which has been machined to have a groove, on the non-piezoelectric base plate, and pasting another non-piezoelectric base plate onto the piezoelectric base plate, an ink chamber can be formed at a low cost and with a high precision owing to the ease of the positional adjustment of the ink chamber.
(20) The method of manufacturing an ink jet head or an ink jet described in one of (17) to (19), further comprising a step of providing an electrode on the non-piezoelectric base plate.
According to this method (21), by providing an electrode on the non-piezoelectric base plate, the electrical connection to an electrode on the piezoelectric base plates can be carried out through the electrode on the non-piezoelectric base plate, the electrical connection with the external power source can be done easily and the efficiency of operation is also improved.
(21) The method of manufacturing an ink jet head or an ink jet described in one of (17) to (20), wherein the ink chamber is formed in multi-stages.
According to this method (21), since the ink chamber is formed in multi-stages, it can carry out a more high-speed and high-quality image recording and can improve resolution of the image with multiple nozzles of the multi-stage ink chamber.
(22) The method of manufacturing an ink jet head or an ink jet described in one of (17) to (21), wherein the piezoelectric base plates are shaped in a flat surface or a curved surface.
According to this method (22), the ink jet head is of low cost owing to the flat surface piezoelectric base plates, or since the amount of deformation of the space forming the ink chamber can be made large by the curved surface, a high-quality image recording can be conducted at a high-speed.
(23) The method of manufacturing an ink jet head or an ink jet described in one of (17) to (22), wherein the piezoelectric base plates have at least two lamination layers which have different lengths in the layer laminating direction.
According to this method (23), because the piezoelectric base plates have at least two layers which have different lengths in the layer laminating direction, the shape of the space making up the ink chamber can be deformed in a manner corresponding to the position of a nozzle hole, and ink can be jetted from the nozzle hole more efficiently.
(24) The method of manufacturing an ink jet head or an ink jet described in one of (17) to (23), wherein the piezoelectric base plates have at least one layer made of a non-piezoelectric material.
According to this method (24), because the piezoelectric base plates have at least one layer made of a non-piezoelectric material, ink can be jetted from a nozzle hole efficiently by deforming the shape of the space making up the ink chamber variously.
(25) A method of manufacturing an ink jet head or an ink jet which jets ink from nozzle holes by applying an electric voltage to an electrode to deform an ink chamber partitioned by partition walls, comprising steps by providing a plurality of piezoelectric base plates which have been given polarization side by side on a non-piezoelectric base plate, machining the piezoelectric base plate so as to form grooves, and thereafter providing another non-piezoelectric base plate on the piezoelectric base plates so that a plurality of ink chambers which are partitioned by partition walls are provided.
According to this method (25), since a plurality of piezoelectric base plates which have been given polarization are provided side by side on a non-piezoelectric base plate, the piezoelectric base plate is machined so as to form grooves, and thereafter another non-piezoelectric base plate is provided on the piezoelectric base plates so that a plurality of ink chambers which are partitioned by partition walls are provided, ink chambers can be formed without lowering positional precision; hence, a high-precision long-sized line head can be obtained at a low cost.
(26) The method of manufacturing an ink jet head or an ink jet described in (25), wherein the grooves are formed at the connecting portions of the plurality of piezoelectric base plates.
According to this structure (26), because the grooves are formed at the connecting portions of the plurality of piezoelectric base plates, the positional precision of the ink chamber can be improved further more.
(27) A method of manufacturing an ink jet head or an ink jet which jets ink from nozzle holes by applying an electric voltage to an electrode to deform an ink chamber partitioned by partition walls, comprising steps by laminating a piezoelectric base plate comprising at least two layers of a piezoelectric material which have different polarizing directions opposite to each other on a non-piezoelectric base plate, machining the piezoelectric base plate so as to form grooves, and thereafter providing another non-piezoelectric base plate on the piezoelectric base plates so that a plurality of ink chambers which are partitioned by partition walls are provided.
According to this method (27), since a piezoelectric base plate comprising at least two layers of a piezoelectric material which have different polarizing directions opposite to each other is laminated on a non-piezoelectric base plate, the piezoelectric base plate is machined so as to form grooves, and thereafter another non-piezoelectric base plate is provided on the piezoelectric base plates so that a plurality of ink chambers which are partitioned by partition walls are provided, ink chambers can be formed without deviation of grooves in the piezoelectric base plates, a high-precision line head can be obtained at a low cost.
(28) A method of manufacturing an ink jet head or an ink jet which jets ink from nozzle holes by applying an electric voltage to an electrode to deform an ink chamber partitioned by partition walls, comprising steps by laminating a piezoelectric base plate comprising at least two layers of a piezoelectric material which have different polarizing directions opposite to each other on a non-piezoelectric base plate, machining the piezoelectric base plate so as to form grooves, and thereafter providing another non-piezoelectric base plate on the piezoelectric base plates so that a plurality of ink chambers which are partitioned by partition walls are provided.
According to this method (28), since a piezoelectric base plate comprising at least two layers of a piezoelectric material which have different polarizing directions opposite to each other is laminated on a non-piezoelectric base plate, the piezoelectric base plate is machined so as to form grooves, and thereafter another non-piezoelectric base plate is provided on the piezoelectric base plates so that a plurality of ink chambers which are partitioned by partition walls are provided, ink chambers can be formed without deviation of grooves in the piezoelectric base plates, a high-precision long-sized line head can be obtained at a low cost.
(29) The method of manufacturing an ink jet head or an ink jet described in (28), wherein the grooves are formed at the connecting portions of the piezoelectric base plates.
According to this method (29), because the grooves are formed at the connecting portions of the plurality of piezoelectric base plates, the ink jet head in which the positional precision of the ink chamber can be improved further more, can be manufactured.
(30) The method of manufacturing an ink jet head or an ink jet described in one of (17) through (29), wherein the piezoelectric base plates is made of a non-metallic material.
According to this method (30), since the piezoelectric base plates is made of a non-metallic material, the ink jet head in which the partition walls of the ink chamber can be deformed more reliably, can be manufactured.
(31) The method of producing an ink jet head or an ink jet described in one of (17) through (29), wherein the material of the non-metallic material is at least one selected from alumina, aluminum nitride, zirconia, silicon, silicon nitride, silicon carbide, and quartz.
According to this method (12), since the material of the non-metallic material is at least one selected from alumina, aluminum nitride, zirconia, silicon, silicon nitride, silicon carbide, and quartz, the ink jet head in which the piezoelectric base plates can be reliably supported even if the partition walls of an ink chamber are deformed, can be manufactured.
(32) The method of producing an ink jet head or an ink jet described in one of (17) through (31), wherein a surface roughness of the bonded surfaces between the non-piezoelectric base plate and the piezoelectric base plates is not larger than 1.0 xcexcm.
According to this method (32), since a surface roughness of the bonded surfaces between the non-piezoelectric base plate and the piezoelectric base plates is not larger than 1.0 xcexcm, the ink jet head in which it is possible to prevent a soft high molecular adhesive (for example, epoxy resin) from entering into the concave portions on the bonded surfaces, the film thickness of the adhesive is practically limited to a minimum, and it is possible to avoid the lowering of sensitivity and the rise of the electric voltage owing to the lowering of the driving force of the piezoelectric base plates, can be manufactured.
(33) The method of producing an ink jet head or an ink jet described in one of (17) through (31), wherein a surface roughness of the bonded surfaces between piezoelectric materials of the piezoelectric base plates having at least two layers of the piezoelectric materials is not larger than 1.0 xcexcm.
According to this method (33), since a surface roughness of the bonded surfaces between piezoelectric materials of the piezoelectric base plates having at least two layers of the piezoelectric materials is not larger than 1.0 xcexcm, the ink jet head in which it is possible to prevent a soft high molecular adhesive (for example, epoxy resin) from entering into the concave portions on the bonded surfaces, the film thickness of the adhesive is practically limited to a minimum, and it is possible to avoid the lowering of sensitivity and the rise of the electric voltage owing to the lowering of the driving force of the piezoelectric base plates, can be manufactured.
(34) The method of producing an ink jet head or an ink jet described in one of (17) through (33), wherein the bonded surfaces between the non-piezoelectric base plate and the piezoelectric base plates are subjected to plasma treatment or UV treatment.
According to this method (34), since the bonded surfaces between the non-piezoelectric base plate and the piezoelectric base plates are subjected to plasma treatment or UV treatment, the ink jet head in which organic contaminants can be cleaned and removed and wetting ability of the surfaces for the adhesive is improved over the whole surface to eliminate poor bonding such as minute bubble remains, and owing to it, poor driving for the piezoelectric base plates can be eliminated, can be manufactured.
(35) The method of producing an ink jet head or an ink jet described in one of (17) through (33), wherein the bonded surfaces between piezoelectric material layers of the piezoelectric base plates having at least two layers of the piezoelectric material are subjected to plasma treatment or UV treatment.
According to this structure (35), since the bonded surfaces between piezoelectric material layers of the piezoelectric base plates having at least two layers of the piezoelectric material are subjected to plasma treatment or UV treatment, the ink jet head in which organic contaminants can be cleaned and removed and wetting ability of the surfaces for the adhesive is improved over the whole surface to eliminate poor bonding such as minute bubble remains, and owing to it, poor driving for the piezoelectric base plates can be eliminated, can be manufactured.